| Message ID | 20211225054647.1750577-1-atishp@rivosinc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Improve RISC-V Perf support using SBI PMU and sscofpmf extension | expand |
On Fri, Dec 24, 2021 at 9:47 PM Atish Patra <atishp@atishpatra.org> wrote: > > This series adds improved perf support for RISC-V based system using > SBI PMU extension[1] and Sscofpmf extension[2]. The SBI PMU extension allows > the kernel to program the counters for different events and start/stop counters > while the sscofpmf extension allows the counter overflow interrupt and privilege > mode filtering. An hardware platform can leverage SBI PMU extension without > the sscofpmf extension if it supports mcounteren at least. Perf stat will work > but record won't work as sscofpmf & mcountinhibit is required to support that. > A platform can support both features event counting and sampling using perf > tool only if sscofpmf is supported. > > This series introduces a platform perf driver instead of a existing arch > specific implementation. The new perf implementation has adopted a modular > approach where most of the generic event handling is done in the core library > while individual PMUs need to only implement necessary features specific to > the PMU. This is easily extensible and any future RISC-V PMU implementation > can leverage this. Currently, SBI PMU driver & legacy PMU driver are implemented > as a part of this series. > > The legacy driver tries to reimplement the existing minimal perf under a new > config to maintain backward compatibility. This implementation only allows > monitoring of always running cycle/instruction counters. Moreover, they can > not be started or stopped. In general, this is very limited and not very useful. > That's why, I am not very keen to carry the support into the new driver. > However, I don't want to break perf for any existing hardware platforms. > If everybody agrees that we don't need legacy perf implementation for older > implementation, I will be happy to drop PATCH 4. > > This series has been tested in Qemu (RV64 & RV32) and HiFive Unmatched. > Qemu patches[4] and OpenSBI v1.0 is required to test it on Qemu and a dt patch > required in U-Boot[5] for HiFive Unmatched. Qemu changes are not > backward compatible. That means, you can not use perf anymore on older Qemu > versions with latest OpenSBI and/or Kernel. However, newer kernel will > just use legacy pmu driver if old OpenSBI is detected. > > The U-Boot patch is just an example that encodes few of the events defined > in fu740 documentation [6] in the DT. We can update the DT to include all the > events defined if required. > > This series depends on the ISA extension parsing series[7]. > > Here is an output of perf stat/report while running perf benchmark with OpenSBI, > Linux kernel and U-Boot patches applied. > > HiFive Unmatched: > ================= > perf stat -e cycles -e instructions -e L1-icache-load-misses -e branches -e branch-misses \ > -e r0000000000000200 -e r0000000000000400 \ > -e r0000000000000800 perf bench sched messaging -g 25 -l 15 > > # Running 'sched/messaging' benchmark: > # 20 sender and receiver processes per group > # 25 groups == 1000 processes run > > Total time: 0.826 [sec] > > Performance counter stats for 'perf bench sched messaging -g 25 -l 15': > > 3426710073 cycles (65.92%) > 1348772808 instructions #0.39 insn per cycle (75.44%) > 0 L1-icache-load-misses (72.28%) > 201133996 branches (67.88%) > 44663584 branch-misses #22.21% of all branches (35.01%) > 248194747 r0000000000000200 (41.94%) --> Integer load instruction retired > 156879950 r0000000000000400 (43.58%) --> Integer store instruction retired > 6988678 r0000000000000800 (47.91%) --> Atomic memory operation retired > > 1.931335000 seconds time elapsed > > 1.100415000 seconds user > 3.755176000 seconds sys > > > QEMU: > ========= > Perf stat: > ========= > > [root@fedora-riscv riscv]# perf stat -e r8000000000000005 -e r8000000000000007 \ > -e r8000000000000006 -e r0000000000020002 -e r0000000000020004 -e branch-misses \ > -e cache-misses -e dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses \ > -e cycles -e instructions perf bench sched messaging -g 15 -l 10 \ > Running with 15*40 (== 600) tasks. > Time: 6.578 > > Performance counter stats for './hackbench -pipe 15 process': > > 1,794 r8000000000000005 (52.59%) --> SBI_PMU_FW_SET_TIMER > 2,859 r8000000000000007 (60.74%) --> SBI_PMU_FW_IPI_RECVD > 4,205 r8000000000000006 (68.71%) --> SBI_PMU_FW_IPI_SENT > 0 r0000000000020002 (81.69%) > <not counted> r0000000000020004 (0.00%) > <not counted> branch-misses (0.00%) > <not counted> cache-misses (0.00%) > 7,878,328 dTLB-load-misses (15.60%) > 680,270 dTLB-store-misses (28.45%) > 8,287,931 iTLB-load-misses (39.24%) > 20,008,506,675 cycles (48.60%) > 21,484,427,932 instructions # 1.07 insn per cycle (56.60%) > > 1.681344735 seconds time elapsed > > 0.614460000 seconds user > 8.313254000 seconds sys > > > [root@fedora-riscv ~]# perf stat -e cycles -e instructions -e dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses \ > > perf bench sched messaging -g 1 -l 10 > # Running 'sched/messaging' benchmark: > # 20 sender and receiver processes per group > # 1 groups == 40 processes run > > Total time: 0.218 [sec] > > Performance counter stats for 'perf bench sched messaging -g 1 -l 10': > > 3,685,401,394 cycles > 3,684,529,388 instructions # 1.00 insn per cycle > 3,006,042 dTLB-load-misses > 258,144 dTLB-store-misses > 1,992,860 iTLB-load-misses > > 0.588717389 seconds time elapsed > > 0.324009000 seconds user > 0.937087000 seconds sys > > [root@fedora-riscv ~]# perf record -e cycles -e instructions -e dTLB-load-misses -e dTLB-store-misses \ > -e iTLB-load-misses -c 10000 perf bench sched messaging -g 1 -l 10 > # Running 'sched/messaging' benchmark: > # 20 sender and receiver processes per group > # 1 groups == 40 processes run > > Total time: 2.160 [sec] > [ perf record: Woken up 11 times to write data ] > Warning: > Processed 291769 events and lost 1 chunks! > > [root@fedora-riscv ~]# perf report > > Available samples > 146K cycles ◆ > 146K instructions ▒ > 298 dTLB-load-misses ▒ > 8 dTLB-store-misses ▒ > 211 iTLB-load-misses > > [1] https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/riscv-sbi.adoc > [2] https://drive.google.com/file/d/171j4jFjIkKdj5LWcExphq4xG_2sihbfd/edit > [3] https://github.com/atishp04/linux/tree/riscv_pmu_v5 > [4] https://github.com/atishp04/qemu/tree/riscv_pmu_v3 > [5] https://github.com/atishp04/u-boot/tree/hifive_unmatched_dt_pmu > [6] https://sifive.cdn.prismic.io/sifive/de1491e5-077c-461d-9605-e8a0ce57337d_fu740-c000-manual-v1p3.pdf > [7] https://lkml.org/lkml/2021/12/24/313 > > Changes from v4->v5: > 1. Fixed few corner case issues in perf interrupt handling. > 2. Changed the set_period API so that the caller can compute the initialize > value. > 3. Fixed the per cpu interrupt enablement issue. > 4. Fixed a bug for the privilege mode filtering. > 5. Modified the sbi driver independent of the DT. > 6. Removed any DT related modifications. > > Changes from v3->v4: > 1. Do not proceed overflow handler if event doesn't set for sampling. > 2. overflow status register is only read after counters are stopped. > 3. Added the PMU DT node for HiFive Unmatched. > > Changes from v2->v3: > 1. Added interrupt overflow support. > 2. Cleaned up legacy driver initialization. > 3. Supports perf record now. > 4. Added the DT binding and maintainers file. > 5. Changed cpu hotplug notifier to be multi-state. > 6. OpenSBI doesn't disable cycle/instret counter during boot. Update the > perf code to disable all the counter during the boot. > > Changes from v1->v2 > 1. Implemented the latest SBI PMU extension specification. > 2. The core platform driver was changed to operate as a library while only > sbi based PMU is built as a driver. The legacy one is just a fallback if > SBI PMU extension is not available. > > Atish Patra (9): > RISC-V: Remove the current perf implementation > RISC-V: Add CSR encodings for all HPMCOUNTERS > RISC-V: Add a perf core library for pmu drivers > RISC-V: Add a simple platform driver for RISC-V legacy perf > RISC-V: Add RISC-V SBI PMU extension definitions > RISC-V: Add perf platform driver based on SBI PMU extension > RISC-V: Add sscofpmf extension support > Documentation: riscv: Remove the old documentation > MAINTAINERS: Add entry for RISC-V PMU drivers > > Documentation/riscv/pmu.rst | 255 ---------- > MAINTAINERS | 9 + > arch/riscv/Kconfig | 13 - > arch/riscv/include/asm/csr.h | 66 ++- > arch/riscv/include/asm/hwcap.h | 1 + > arch/riscv/include/asm/perf_event.h | 72 --- > arch/riscv/include/asm/sbi.h | 97 ++++ > arch/riscv/kernel/Makefile | 1 - > arch/riscv/kernel/cpufeature.c | 1 + > arch/riscv/kernel/perf_event.c | 485 ------------------ > drivers/perf/Kconfig | 30 ++ > drivers/perf/Makefile | 5 + > drivers/perf/riscv_pmu.c | 330 ++++++++++++ > drivers/perf/riscv_pmu_legacy.c | 143 ++++++ > drivers/perf/riscv_pmu_sbi.c | 762 ++++++++++++++++++++++++++++ > include/linux/cpuhotplug.h | 1 + > include/linux/perf/riscv_pmu.h | 73 +++ > 17 files changed, 1517 insertions(+), 827 deletions(-) > delete mode 100644 Documentation/riscv/pmu.rst > delete mode 100644 arch/riscv/kernel/perf_event.c > create mode 100644 drivers/perf/riscv_pmu.c > create mode 100644 drivers/perf/riscv_pmu_legacy.c > create mode 100644 drivers/perf/riscv_pmu_sbi.c > create mode 100644 include/linux/perf/riscv_pmu.h > > -- > 2.33.1 > Apologies for multiple emails on this series (in case you are subscribed to linux-kernel@vger.kernel.org as well). I messed up my script earlier and it removed all the CC entries and sent the email just to lkml by mistake. Sorry for the noise.
This series adds improved perf support for RISC-V based system using SBI PMU extension[1] and Sscofpmf extension[2]. The SBI PMU extension allows the kernel to program the counters for different events and start/stop counters while the sscofpmf extension allows the counter overflow interrupt and privilege mode filtering. An hardware platform can leverage SBI PMU extension without the sscofpmf extension if it supports mcounteren at least. Perf stat will work but record won't work as sscofpmf & mcountinhibit is required to support that. A platform can support both features event counting and sampling using perf tool only if sscofpmf is supported. This series introduces a platform perf driver instead of a existing arch specific implementation. The new perf implementation has adopted a modular approach where most of the generic event handling is done in the core library while individual PMUs need to only implement necessary features specific to the PMU. This is easily extensible and any future RISC-V PMU implementation can leverage this. Currently, SBI PMU driver & legacy PMU driver are implemented as a part of this series. The legacy driver tries to reimplement the existing minimal perf under a new config to maintain backward compatibility. This implementation only allows monitoring of always running cycle/instruction counters. Moreover, they can not be started or stopped. In general, this is very limited and not very useful. That's why, I am not very keen to carry the support into the new driver. However, I don't want to break perf for any existing hardware platforms. If everybody agrees that we don't need legacy perf implementation for older implementation, I will be happy to drop PATCH 4. This series has been tested in Qemu (RV64 & RV32) and HiFive Unmatched. Qemu patches[4] and OpenSBI v1.0 is required to test it on Qemu and a dt patch required in U-Boot[5] for HiFive Unmatched. Qemu changes are not backward compatible. That means, you can not use perf anymore on older Qemu versions with latest OpenSBI and/or Kernel. However, newer kernel will just use legacy pmu driver if old OpenSBI is detected. The U-Boot patch is just an example that encodes few of the events defined in fu740 documentation [6] in the DT. We can update the DT to include all the events defined if required. This series depends on the ISA extension parsing series[7]. Here is an output of perf stat/report while running perf benchmark with OpenSBI, Linux kernel and U-Boot patches applied. HiFive Unmatched: ================= perf stat -e cycles -e instructions -e L1-icache-load-misses -e branches -e branch-misses \ -e r0000000000000200 -e r0000000000000400 \ -e r0000000000000800 perf bench sched messaging -g 25 -l 15 # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 25 groups == 1000 processes run Total time: 0.826 [sec] Performance counter stats for 'perf bench sched messaging -g 25 -l 15': 3426710073 cycles (65.92%) 1348772808 instructions #0.39 insn per cycle (75.44%) 0 L1-icache-load-misses (72.28%) 201133996 branches (67.88%) 44663584 branch-misses #22.21% of all branches (35.01%) 248194747 r0000000000000200 (41.94%) --> Integer load instruction retired 156879950 r0000000000000400 (43.58%) --> Integer store instruction retired 6988678 r0000000000000800 (47.91%) --> Atomic memory operation retired 1.931335000 seconds time elapsed 1.100415000 seconds user 3.755176000 seconds sys QEMU: ========= Perf stat: ========= [root@fedora-riscv riscv]# perf stat -e r8000000000000005 -e r8000000000000007 \ -e r8000000000000006 -e r0000000000020002 -e r0000000000020004 -e branch-misses \ -e cache-misses -e dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses \ -e cycles -e instructions perf bench sched messaging -g 15 -l 10 \ Running with 15*40 (== 600) tasks. Time: 6.578 Performance counter stats for './hackbench -pipe 15 process': 1,794 r8000000000000005 (52.59%) --> SBI_PMU_FW_SET_TIMER 2,859 r8000000000000007 (60.74%) --> SBI_PMU_FW_IPI_RECVD 4,205 r8000000000000006 (68.71%) --> SBI_PMU_FW_IPI_SENT 0 r0000000000020002 (81.69%) <not counted> r0000000000020004 (0.00%) <not counted> branch-misses (0.00%) <not counted> cache-misses (0.00%) 7,878,328 dTLB-load-misses (15.60%) 680,270 dTLB-store-misses (28.45%) 8,287,931 iTLB-load-misses (39.24%) 20,008,506,675 cycles (48.60%) 21,484,427,932 instructions # 1.07 insn per cycle (56.60%) 1.681344735 seconds time elapsed 0.614460000 seconds user 8.313254000 seconds sys [root@fedora-riscv ~]# perf stat -e cycles -e instructions -e dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses \ > perf bench sched messaging -g 1 -l 10 # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 1 groups == 40 processes run Total time: 0.218 [sec] Performance counter stats for 'perf bench sched messaging -g 1 -l 10': 3,685,401,394 cycles 3,684,529,388 instructions # 1.00 insn per cycle 3,006,042 dTLB-load-misses 258,144 dTLB-store-misses 1,992,860 iTLB-load-misses 0.588717389 seconds time elapsed 0.324009000 seconds user 0.937087000 seconds sys [root@fedora-riscv ~]# perf record -e cycles -e instructions -e dTLB-load-misses -e dTLB-store-misses \ -e iTLB-load-misses -c 10000 perf bench sched messaging -g 1 -l 10 # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 1 groups == 40 processes run Total time: 2.160 [sec] [ perf record: Woken up 11 times to write data ] Warning: Processed 291769 events and lost 1 chunks! [root@fedora-riscv ~]# perf report Available samples 146K cycles ◆ 146K instructions ▒ 298 dTLB-load-misses ▒ 8 dTLB-store-misses ▒ 211 iTLB-load-misses [1] https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/riscv-sbi.adoc [2] https://drive.google.com/file/d/171j4jFjIkKdj5LWcExphq4xG_2sihbfd/edit [3] https://github.com/atishp04/linux/tree/riscv_pmu_v5 [4] https://github.com/atishp04/qemu/tree/riscv_pmu_v3 [5] https://github.com/atishp04/u-boot/tree/hifive_unmatched_dt_pmu [6] https://sifive.cdn.prismic.io/sifive/de1491e5-077c-461d-9605-e8a0ce57337d_fu740-c000-manual-v1p3.pdf [7] https://lkml.org/lkml/2021/12/24/313 Changes from v4->v5: 1. Fixed few corner case issues in perf interrupt handling. 2. Changed the set_period API so that the caller can compute the initialize value. 3. Fixed the per cpu interrupt enablement issue. 4. Fixed a bug for the privilege mode filtering. 5. Modified the sbi driver independent of the DT. 6. Removed any DT related modifications. Changes from v3->v4: 1. Do not proceed overflow handler if event doesn't set for sampling. 2. overflow status register is only read after counters are stopped. 3. Added the PMU DT node for HiFive Unmatched. Changes from v2->v3: 1. Added interrupt overflow support. 2. Cleaned up legacy driver initialization. 3. Supports perf record now. 4. Added the DT binding and maintainers file. 5. Changed cpu hotplug notifier to be multi-state. 6. OpenSBI doesn't disable cycle/instret counter during boot. Update the perf code to disable all the counter during the boot. Changes from v1->v2 1. Implemented the latest SBI PMU extension specification. 2. The core platform driver was changed to operate as a library while only sbi based PMU is built as a driver. The legacy one is just a fallback if SBI PMU extension is not available. Atish Patra (9): RISC-V: Remove the current perf implementation RISC-V: Add CSR encodings for all HPMCOUNTERS RISC-V: Add a perf core library for pmu drivers RISC-V: Add a simple platform driver for RISC-V legacy perf RISC-V: Add RISC-V SBI PMU extension definitions RISC-V: Add perf platform driver based on SBI PMU extension RISC-V: Add sscofpmf extension support Documentation: riscv: Remove the old documentation MAINTAINERS: Add entry for RISC-V PMU drivers Documentation/riscv/pmu.rst | 255 ---------- MAINTAINERS | 9 + arch/riscv/Kconfig | 13 - arch/riscv/include/asm/csr.h | 66 ++- arch/riscv/include/asm/hwcap.h | 1 + arch/riscv/include/asm/perf_event.h | 72 --- arch/riscv/include/asm/sbi.h | 97 ++++ arch/riscv/kernel/Makefile | 1 - arch/riscv/kernel/cpufeature.c | 1 + arch/riscv/kernel/perf_event.c | 485 ------------------ drivers/perf/Kconfig | 30 ++ drivers/perf/Makefile | 5 + drivers/perf/riscv_pmu.c | 330 ++++++++++++ drivers/perf/riscv_pmu_legacy.c | 143 ++++++ drivers/perf/riscv_pmu_sbi.c | 762 ++++++++++++++++++++++++++++ include/linux/cpuhotplug.h | 1 + include/linux/perf/riscv_pmu.h | 73 +++ 17 files changed, 1517 insertions(+), 827 deletions(-) delete mode 100644 Documentation/riscv/pmu.rst delete mode 100644 arch/riscv/kernel/perf_event.c create mode 100644 drivers/perf/riscv_pmu.c create mode 100644 drivers/perf/riscv_pmu_legacy.c create mode 100644 drivers/perf/riscv_pmu_sbi.c create mode 100644 include/linux/perf/riscv_pmu.h -- 2.33.1